A. Field of the Invention
The present invention relates to a method of producing aluminum impact extrusions having high ductility, and more particularly to a method of producing highly ductile impact extrusions having outstanding subsequent fabrication characteristics from slugs of aluminum base alloy containing cobalt and/or nickel by impact extruding the slug by an impact press and annealing the extruded product.
B. Description of the Prior Art
Impact extrusions can be produced from any commercial aluminum alloy, but the stock most extensively used for impact extrusion is a commercial pure aluminum having a purity of 99.5 to 99.8% by weight because of its impact extrusion characteristics and its properties in the finished product. Collapsible tubes, for example, are produced by impact extruding a slug of commercial pure aluminum having a purity of 99.7% by weight or more and annealing the resulting extrusion to the state of soft temper. The tubes are used as containers for toothpastes, foods, drugs, etc.
However, such collapsible tubes, when filled with contents, are liable to break where they are frequently flexed during repeated use, possibly permitting leakage of the contents. It is therefore desired to provide collapsible aluminum tubes which are not easily breakable. To assure economy of transport, there is also a great demand for collapsible taper tubes which are prepared from impact extrusions by subsequent fabrication. Various other impact extrusion products are similarly produced by subjecting impact extrusions to necking, drawing or the like. Conventional impact extrusion products nevertheless are not always satisfactory in subsequent fabrication characteristics but are likely to break or become otherwise defective in the course of subsequent fabrication. Thus it is also desired to develop aluminum impact extrusions having outstanding subsequent fabrication characteristics.